Cellulose acetate composition



Patented Oct. 6, 1931 UNITED sTATEs PATENT curios ALBERT F. SULZER, OF ROCHESTER, YORK, ASSIGNOR, TO. EASTMAN KODAK COM- PANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK CELLULOSE ACETATE COM POSITION Ho Drawing.

5 plastic'and analogous arts,- such for instance,

as film manufacture and varnish manufacture. One object of the invention is to provide a composition which may be made into permanently transparent, strong'and flexible sheets or fihns of desired thinness, which are substantially water-proof, are unaflected by ordinary photographic fluid treatments, possess the desired roperties of a support for light-sensitive p otographic coatings, and are of low inflammability. Other objects will hereinafter appear. I

I have found that a composition having the desirable ualities hereinabove enumerated can be pr ganic esters of cellulose, cellulose ether, or

even cellulose nitrate, with one or more phosphoric esters of the alkyl ethers of the polyethylene glycols. Such esters may be derived from ethers or di, tri or tetraethylene glycol, the ether groups being preferably methyl, ethyl, propyl, but 1 or amyl. The formulae for the various et ers mentioned are as follows, R representing either a' methyl, ethyl,

propyl, butyl or amyl group: Dlethylene glycol monoalkyl ether n-o cmcn -o-cmcn on Trlethylene glycol monoalkyl ether R-O-CHgCHz-O-CHzCHz-O-CHgCHgOH Tetraethylene lycol monoalk l ether n-o-ohzcnrocngc n -o-cn cnz-o-cngcmon The phosphoric esters referred to may be repared from preferably the monoalkyl et ers of the polyethylene glycols by any conventional esterifying method, such as by reacting upon the ester with phosphorus oxychlorid OCl until evolution of hydrochloric acld stops. The esters thus produced are the ortho phosphoric esters those normally utilized) and have the general formula: 1

where R is everything in the above other for- }59 mulae with the except on 'of the termmal OH need by mixing cellulose derivaa tives, such as cellulose acetate, or other orf p qu y film resulting from; the P the ortho esters being Application filed May 9, 1927. Serial No. 190,147.

group. These phosphoric esters are then hydrolized to the dihydrogen alkyl ether of the glycol involved giving a compound having t e general formula:

R'--0 O HO- PO Hydrolysis of the ether to. the dihydrogen compound appears'to be the more convenient and hence the more economical of those mentioned. 1

The phosphoric esters described have a distinct solvent action toward the cellulose derivatives mentioned and although this solubility is not great, nevertheless, films that are formed from a dope or composition containing these esters are brilliantly transparent. The difliculty often experienced of cipitation of the high boilers which have low 70 solubility is not experienced when these esters are used.

In carrying out an illustrative embodiment of my invention, 100 parts of cellulose ace- 1'75 tate of the'ace'tone-soluble species are dissolved along with 2 to 50 parts (say 20) by weight of the dihydrogen phosphoric ester of the monoethyl ether of tetraethylene gly- 001' in a volatile liquid containing a 001111110113 0 solvent, say 300 to 600 parts of acetone. While the phosphoric esters of monoalkyl polyethylene glycols have solvent action with respect to cellulose acetate by themselves, nevertheless it is desirable to have a volatile: solvent. present also. This gives a fiowable film-forming composition or dope suitable for spreading out into coatings, which upon the evaporation of the common solvent leave transparent, tough, flexible sheets of low in-' flammability. The customary film making processes and apparatus may be used with the solution. In place of the cellulose acetate in the aboveexample, there may be substituted an equal weight of cellulose nitrate, such as is commonly used in fihn manufacture, or mixtures of cellulose nitrate and cellulose acetate may be substituted. Likewise I mayreplace the cellulose acetate, weight a for weight, .withany of the acetone-soluble" 100 2 Leeaeei organic esters of cellulose disclosed in the weight of the dihydrogen phosphoric ester of a plication of Hans T. Clarke and Carl J. the monoethyl ether oit'tetraethylene glycol, 1V alm, Serial No. 179,177, filed March 28th, and over 300 parts of a liquid vehicle includ- 1927, for process of making cellulose esters ing a common volatile solvent. of organic acids. 1 can also employ ethyl Signed at Rochester, New York, this 3rd to cellulose in place of cellulose acetate using, day of May, 1927. I however,as the common solvent, a mixture of ALBERT 1?. SEE. equal parts of ethyl alcohol and chloroform instead of acetone. w Where compositions of greater ability to flow are desired, the amount of volatile solvent may be increased and diluents, such as benzol, ethyl alcohol, methyl alcohol, and the like may be added, although they should not 35 be in such an excess as to produce precipitaso tion or the production of a hazy or whitish film. In order to control the rate of the evaporation, substances of low or intermedi ate volatility ma be added, such as the 29 higher alcohols li e the various propyl, bu-

tyl and amyl alcohols, or mixtures of them. An amount of butyl alcohol, for example, which is useful, m'ay be approximately onetenth to one-fifth of the weight of the cellulose acetate in the above formula. Part of l this alcohol will remain in the film and en= hance its flexibility. Other substances of low volatility ma be used, such as camphor, monochlornapht alene, and the like. The proportion of these, or any mixture of them,

should not, however, be 'suficient to cause premature precipitation or whitenin during the use of the solution, especially w ere the I latter is to be made into photographic film.

and are purified sufliciently for the purposes to which they are put, those for film manu facture being chosen so as to have the customary practical freedom from color, and tree'- dom from impurities which would impair the transparency or injure the emulsions.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A composition of matter comprising a .110 cellulose derivative and a phosphoric ester of an alkyl ether of a polyethyleneglycol.

2. A. composition of matter comprising a cellulose derivative and a phosphoric ester of a monoalkyl ether of tetraethylene glycol. Y 1 M5 3. A composition of matter comprising a cellulose derivative and the dihydrogen phosphoric ester of the monoethyl ether of tetraethylene glycol.

4. composition in a colloidized state comprising cellulose acetate and a phos horic eslter pf a monoalkyl ether of a polyet ylene g yco s 5. A flowable film-formingcomposition comprising cellulose acetate, a phosphoric es- 325 ter of a monoalkyl ether of tetraethylene glycol, and acommon volatile solvent.

6. fiowable film-forming composition comprising parts by weight of acetonea 55 .soluble cellulose acetate, 2 to 5 0 parts by The ingredients are of the commercial type 4 i 

